1. Technical Field
The present specification relates to a hybrid vehicle, and more particularly to a hybrid vehicle having an engine, a planetary gear, first and second motors, first and second inverters, and a battery.
2. Description of Related Art
A vehicle having an engine, a power split mechanism (a planetary gear mechanism), first and second motors, first and second inverters, a converter, and a battery has been proposed as a conventional hybrid vehicle of this type (see Japanese Patent Application Publication No. 2013-203116 (JP 2013-203116 A), for example). Here, a rotor of the first motor is connected to a sun gear of the power split mechanism. A crankshaft of the engine is connected to a carrier of the power split mechanism. An output member coupled to an axle is connected to a ring gear of the power split mechanism. A rotor of the second motor is connected to the output member. The converter boosts power on the battery side and supplies the boosted power to the side of the first and second inverters, and steps down power on the side of the first and second inverters and supplies the stepped-down power to the battery side. In this hybrid vehicle, when a fault occurs in the first and second inverters while the engine is operative, respective gates of the first and second inverters are both blocked. A rotation speed of the engine is then controlled in accordance with a direct current side voltage of the inverter, a rotation speed of the output member, and a condition of an accelerator so that a counter-electromotive voltage generated as the first motor rotates exceeds the direct current side voltage of the inverter. In so doing, braking torque derived from the counter-electromotive voltage of the first motor is adjusted, and accordingly, reaction torque (drive torque generated by the output member) to the braking torque is adjusted.
In the hybrid automobile described above, it may be difficult to adjust the rotation speed of the engine in cases where the direct current side voltage of the inverter cannot be detected or the like. It is therefore necessary to enable appropriate travel using a method other than the method described above when a fault occurs in the first and second inverters while the engine is operative.